In Etidorhapa,
chapters XV and XXXI deal with volcanoes:
Best Online Casinos Australia - Trusted AU Pokies Picks Best Online Casinos Australia - Trusted AU Pokies Picks
Etidorhpa on Volcanoes
" Know then, that the theories of man concerning volcanic eruptions,
in
connection with a molten interior of the Earth, are such as are
evolved in
ignorance of even the subsurface of the globe. The earth's interior
is to
mankind a sealed chamber, and the wise men who elucidate the curious
theories concerning natural phenomena occurring therein are forced to
draw
entirely upon their imagination. Few persons realize the paucity of
data at
the command of workers in science. Theories concerning the earth are
formulated from so little real knowledge of that body, that our
science may
be said to be all theory, with scarcely a trace of actual evidence to
support it. If a globe ten inches in diameter be covered with a sheet
of
paper, such as I hold in my hand, the thickness of that sheet will be
greater in proportion to that of such a globe than the depth men have
explored within the earth is compared with the thickness of the crust
of the
earth. The outer surface of a pencil line represents the surface of
the
earth; the inner surface of the line represents the depth of man's
explorations; the highest mountain would be represented by a comma
resting
on the line. The geologist studies the substances that are thrust
from the
crater of an active volcano, and from this makes conjectures
regarding the
strata beneath, and the force that casts the excretions out. The
results
must with men, therefore, furnish evidence from which to explain the
cause.
It is as though an anatomist would form his idea of the anatomy of
the liver
by the secretion thrown out of that organ, or of the lung texture by
the
breath and sputum. In fact, volcanoes are of several descriptions,
arid
usually are extremely- superficial. This lake, the surface of which
is but
one hundred and fifty miles underground, is the mother of an
exceptionally
deep one. When the water pours over this ledge it strikes alt element
below
us, the metallic base of salt, which lies in great masses in some
portions
of the earth's crust. Then an immediate chemical reaction ensues, the
water is dissociated, intense heat results, part of the water
combines with
the metal, part is vaporized as steam, while part escapes as an
inflammable
gas. The sudden liberation of these gases causes an irregular
pressure of
vapor on the surface of the lake, the result being a throbbing and
rebounding of the attenuated atmosphere above, which, in gigantic
waves,
like swelling tides, dashes great volumes of water over the ledge
beside us,
and into the depth below. This water in turn reacts on fresh portions
of the
metallic base, and the reflex action increases the vapor discharges,
and as
a consequence the chamber we are in becomes a gasholder, containing
vapors
of unequal gas pressures, and the resultant agitation of the lake
from the
turmoil continues, and the pulsations are repeated until the surface
of the
lake is lowered to such a degree as at last to prevent the water from
overflowing the barrier. Finally the lake quiets itself, the gases
slowly
disappear by earth absorption, and by escape from the volcanic exit,
and for
an unrecorded period of time thereafter the surface of the lake
continues to
rise slowly as it is doing now."
" But what has this phenomenon to do with the volcano?"
" It produces the eruption; the water that rushes down into the chasm,
partly as steam, partly as gas, is forced onward and upward through a
crevice that leads to the old crater of the presumed extinct but
periodically active Mount Epomeo. These gases are intensely heated,
and they
move with fearful velocity. They tear off great masses of stone,
which the
resultant energy disturbances, pressure, gas, and friction, redden
with
heat. The mixture of gases from the decomposed water is in large
amount, is
burning and exploding, and in this fiery furnace amid such
convulsions as
have been described, the adjacent earth substance is fused, and even
clay is
melted, and carried on with the fiery blast. Finally the current
reaches the
earth's surface through the funnel passage, the apex of which is a
volcano-the blast described a volcanic eruption."